Files
dsrpc/header.go
2023-05-17 12:52:41 +02:00

102 lines
2.1 KiB
Go

/*
*
* Copyright 2022 Oleg Borodin <borodin@unix7.org>
*
*/
package dsrpc
import (
"bytes"
"encoding/binary"
"encoding/json"
"errors"
)
const (
headerSize int64 = 16 * 2
sizeOfInt64 int = 8
magicCodeA int64 = 0xEE00ABBA
magicCodeB int64 = 0xEE44ABBA
)
type Header struct {
magicCodeA int64 `json:"magicCodeA"`
rpcSize int64 `json:"rpcSize"`
binSize int64 `json:"binSize"`
magicCodeB int64 `json:"magicCodeB"`
}
func NewEmptyHeader() *Header {
return &Header{
magicCodeA: magicCodeA,
magicCodeB: magicCodeB,
}
}
func (hdr *Header) ToJson() []byte {
jBytes, _ := json.Marshal(hdr)
return jBytes
}
func (hdr *Header) Pack() ([]byte, error) {
var err error
headerBytes := make([]byte, 0, headerSize)
headerBuffer := bytes.NewBuffer(headerBytes)
magicCodeABytes := EncoderI64(hdr.magicCodeA)
headerBuffer.Write(magicCodeABytes)
rpcSizeBytes := EncoderI64(hdr.rpcSize)
headerBuffer.Write(rpcSizeBytes)
binSizeBytes := EncoderI64(hdr.binSize)
headerBuffer.Write(binSizeBytes)
magicCodeBBytes := EncoderI64(hdr.magicCodeB)
headerBuffer.Write(magicCodeBBytes)
return headerBuffer.Bytes(), err
}
func UnpackHeader(headerBytes []byte) (*Header, error) {
var err error
headerReader := bytes.NewReader(headerBytes)
magicCodeABytes := make([]byte, sizeOfInt64)
headerReader.Read(magicCodeABytes)
rpcSizeBytes := make([]byte, sizeOfInt64)
headerReader.Read(rpcSizeBytes)
binSizeBytes := make([]byte, sizeOfInt64)
headerReader.Read(binSizeBytes)
magicCodeBBytes := make([]byte, sizeOfInt64)
headerReader.Read(magicCodeBBytes)
header := &Header{
magicCodeA: DecoderI64(magicCodeABytes),
rpcSize: DecoderI64(rpcSizeBytes),
binSize: DecoderI64(binSizeBytes),
magicCodeB: DecoderI64(magicCodeBBytes),
}
if header.magicCodeA != magicCodeA || header.magicCodeB != magicCodeB {
err = errors.New("Wrong protocol magic code")
return header, err
}
return header, err
}
func EncoderI64(i int64) []byte {
buffer := make([]byte, sizeOfInt64)
binary.BigEndian.PutUint64(buffer, uint64(i))
return buffer
}
func DecoderI64(b []byte) int64 {
return int64(binary.BigEndian.Uint64(b))
}